DNA has been proposed as a highly desirable medium for storage of digital information. The barrier to such use of DNA is the low efficiency and speed as well as the high cost of current synthesis methods. In the current state of the art, DNA is synthesized using phosphoramidite precursors in organic solvents. These chemical synthesis methods result in errors of approximately 1% and take approximately 10 minutes per addition step. Furthermore, the reagents that are used in this synthesis process are expensive. Some of these same reagents also damage DNA, a problem that precludes the possibility of synthesizing DNA strands that are longer than ˜200 bases, further hampering the efficiency of this chemical process. TdT is currently used in batch reactions for the addition of variable lengths of singular nucleotides or uncontrolled sequence of nucleotide mixtures to the 3′ end of a nucleic acid sequence. A need remains for the development of faster and cheaper enzymatic oligonucleotide synthesis methods than the existing chemical oligonucleotide synthesis methods.